Many studies, the first done more than 50 years ago, have demonstrated that genes play an important role in regulating the development of alcoholism in humans. Unfortunately, only limited progress has been made towards actually identifying genes that contribute to alcoholism. Animal models may be of some utility in this respect. Many studies done at the University of Colorado, as well as other places, have demonstrated that genes regulate many alcohol-induced and-related behaviors. Much of our early work was devoted to determining whether genes influence alcohol phenotypes. One area of particular success was the development of the long-sleep (LS) and short-sleep (SS) mouse lines. These lines were derived by selective breeding starting from the outbred, heterogeneous stock (HS) mice. In recent years we have been searching for the genes that regulate the sleep time phenotype. Congenic strains and recombinant inbred strains have been developed from the LS and SS mice that will be very useful in identifying genes that regulate the sleep time phenotype. Perhaps of greater importance, these mice have already proven to be of value in studying many other alcohol phenotypes. We have also developed mouse lines (HAFT-LAFT) that differ from acute functional tolerance (first dose tolerance) to alcohol, via selective breeding from the HS stock. These mice are a very valuable and unique resource that must be maintained. This R24 application is being submitted to help guarantee the continued success of alcohol genetics research at the University of Colorado and so that we can continue to supply our valuable animals to other researchers.